The files, which were obtained by Bloomberg News, reveal that the investigation focused on Ivana's connections in her home country of Czechoslovakia, and spanned several countries. The nature of the inquiry remains unknown, but the documents show that the FBI's counterintelligence division was involved and that the agency redacted significant portions of the files citing national security concerns and personal privacy.
The documents, which were classified as "secret," also reveal that the FBI looked into her association with individuals whose names are redacted from the release. The inquiry lasted at least two years and included inquiries into Ivana's emigration from Czechoslovakia to Austria and Canada, as well as her divorce from Donald Trump.
The documents also show that the FBI investigated a man connected to Czechoslovakian intelligence who arranged fictitious marriages and was believed to have some connection to Ivana Trump.
But, the FBI also noted that, "it is unknown if the allegations stem from jealousies of her wealth and fame. Investigation continuing."
The FBI released 190 pages of records on Monday, and said it would release the remainder next month.
Ivana and Donald Trump married in 1977 and had three children: Donald Jr., Ivanka and Eric Trump. They divorced in 1992. Ivana Trump passed away last July at the age of 73.